CHAPTER LXXVII. 
REPORT ON THE GEOLOGY OF LOGAN COUNTY. 
BY FRANKLIN C. HILL. 
SITUATION AND AREA. 
Logan county lies just north of the middle of the western half of the’ 
State, and is bounded on the north by Auglaize and Hardin counties, on 
the east by Union, on the south by Champaign, and on the west by 
Shelby and Auglaize. Its boundaries are chiefly section lines, and its 
general form is that of a rectangle, about twenty-four and one-half miles 
long, east and west, by eighteen and a half miles north and south, and its 
area is about four hundred and fifty-three square miles, or two hundred 
and ninety thousand acres. 
NATURAL DRAINAGE. 
The boundary lines of the county are all nearly ievel, and hold an ele- 
vation of between one thousand and twelve hundred feet above tide- 
water, falling where the Miami River goes out on the west to about nine 
hundred and seventy-five feet, but the center has been upheaved until 
the summit, on John W. Hogue’s farm, one and one-half miles east of 
Bellefontaine, has reached the height of one thousand five hundred and 
forty feet, which equals one thousand one hundred and eight feet above 
low-water at Cincinnati, and nine hundred and seventy-five feet above 
Lake Erie, and is the highest point yet measured in Ohio. 
Thus the general form of the county is that of a flat cone, about five 
hundred feet in height. 
This cone has been cleft from north to south to the depth of some three 
hundred feet by the valley of Mad River, leaving a summit on the east, 
at Wickersham’s Corners (called “Jerusalem” on the county map) only 
twenty-five feet lower than the one on Hogue’s farm. , 
The waters falling on Hogue’s summit, and flowing through the streets 
of Bellefontaine, as “‘ Possum Run,” fall into Blue Jacket, thence into 
Buckinjehala, and so into the great Miami, whence they are taken, at 
Port Jefferson, into the Summit-level of the Miami canal, and these are 
divided, part flowing southward into the Ohio and the Mexican Gulf, 
and part going northward to Lake Erie and the St. Lawrence. 
